This program is directed primarily at an increased understanding of the regulation of the peripheral circulation. It approaches this regulation on a variety of levels, extending from the effects of emotion to the effects of peripheral receptors, such as baroreceptors and chemoreceptors, through a consideration of the regulation of particular vascular beds (e.g., coronary, skin, muscle, splanchnic), distribution of blood flow, and a detailed examination of the regulation of the microcirculation. Experimental preparations are also widely distributed, extending from anesthetized animal preparations through intact, unanesthetized experimental animals and humans. We seek to investigate the details of regulation in arterioles, precapillary sphincters, i.e., at the sites where ultimate control is investigated, and to investigate the details and relative importance of local metabolic control versus autonomic control. We will investigate the existence of "patterns" in the autonomic discharge to various organs and the changes in these autonomic patterns under a variety of stresses. Where possible, we will produce a quantitative description of the phenomena under study. This description extends to understanding the quantitative significance of regional vasomotor activity in the redistribution of blood flow and in the regulation of total peripheral resistance and blood pressure. Thus, the ultimate goals of the study are both broad and narrow.